Various devices for sealing the hasps or staples of locks or latches which secure containers such as railroad boxcars, trucks semi-trailers, intermodal containers, barrels, electrical equipment containers and the like, have long been used as a means of assuring the security and integrity of the goods or items contained therein. Typical of such devices is a seal which comprises an elongated, flexible sealing wire and a metal seal. The wire is passed through the hasp or staple and then its ends are retained by the metal seal which is crimped or deformed to prevent removal of the wire ends. Since the presence of the wire prevents operation of the harp or staple, unauthorized entry into the container entails rendering the metal seal or the wire disintegral, thus creating visual evidence of the unauthorized entry.
The invention of commonly assigned application Ser. No. 424,892 filed Oct. 20, 1989 now U.S. Pat. No. 4,978,026 issued Dec. 18, 1990 represents an improvement over the crimped or deformable metal seal. Specifically the '026 invention is a seal which includes a flexible seal wire and two partially interfitted, relatively rotatable members. A flexible seal wire is passed through a hasp, staple or other locking facility and then its ends are inserted through aligned apertures in both of the partially interfitted members. Relative rotation is then imparted between the partially interfitted members to cause the wire to be wrapped around one member and thereby deformed and locked between the members. The members are then completely interfitted to further deform the wire and lock them together.
The improved seal of the '026 patent is less costly than prior art seals because the members may be made of molded plastic by automated equipment. The improved seal also gives a more definite visual indication of unauthorized entry since tampering with the members cracks, chips or crazes them to provide visual evidence of tampering and, if they are rendered disintegral, they are difficult, if not impossible, to put back together.
Examples of other prior art devices predating the '026 patent may be found in U.S. Pat. Nos. 421,951 and 1,911,060.
U.S. Pat. No. 421,951 issued Feb. 25, 1890, discloses a rotatable seal lock wherein a strip seal is inserted within a rotatable member. Thereafter the member is rotated causing a dog to be received within an opening in the strip and pulled within the rotatable member to a retained position. The rotatable member is held against unlocking rotation by the use of a spring-loaded pawl.
U.S. Pat. No. 1,911,060, issued May 23, 1933, discloses a sealing device having a body with apertures through which a flexible sealing means can extend. The center portion of the body is provided with a threaded bore which is intersected by the apertures. Disposed within the threaded bore is a uni-rotational screw which may be tightened down against the flexible securing means to retain it in a sealed position.
While the foregoing seals are beneficial, a need remains for a simple seal capable of securing a container, the seal providing clear evidence of tampering and being economical to manufacture. Further, although the invention of '026 patent represents a major advance over earlier devices, it is desirable to simplify the assembly and use of its seal and to further ensure that such seal cannot be taken apart or rendered disintegral and then later reassembled.
One object of the present invention is to achieve the foregoing desiderata.
It is another object of the present invention to provide a seal that is highly resistant to tampering.
It is a further object of the present invention to provide a seal that provides an indication of any tampering action and which cannot be reassembled after being rendered disintegral.
An additional object of the present invention is to provide a seal which is economical to manufacture and simple to use while at the same time being highly secure.